Neurodegenerative disorders are often classified based on abnormalities in α-synuclein (α-syn) or tau protein, such abnormalities typically being identified during a pathological analysis. As a result, a neurodegenerative disorder is typically classified as either a synucleinopathy or a tauopathy, with the two categories often being viewed as two distinct types of clinical and pathological entity
This view is consistent with the most obvious clinical manifestations of common disorders in each category. For example, the most common disorder classed as a synucleinopathy, Parkinson's Disease (PD), is characterized by extrapyramidal motor dysfunction, whereas the most common tauopathy, Alzheimer's Disease (AD) is defined by dementia, as is another relatively common tauopathy, Frontotemporal Dementia (FTD).
Despite this, there are considerable overlaps in the clinical symptoms of the synucleinopathies and tauopathies. For example, PD patients frequently have dementia, and AD and FTD patients often manifest parkinsonism. Dementia with Lewy bodies (DLB), although defined as a synucleinopathy, exemplifies the existence of a continuum between the clinical symptoms of the synucleinopathies and of the tauopathies. This continuum leads to difficulties when attempting to accurately diagnose a patient, particularly at an early stage in their illness.
Accordingly, there is a need for the development of a reliable diagnostic test which can discriminate between different neurological disorders.